This invention relates to spread spectrum communications using pseudo noise codes and more particularly to the synchronizing of a locally generated pseudo noise code to that of the transmitted code.
In spread spectrum communications utilizing pseudo noise codes the receiving unit must generate a pseudo noise code to be synchronized with the pseudo noise code in the received signal. This synchronization process is accomplished before data can be transmitted over the communications link. The ability to synchronize and the speed at which synchronization can be accomplished are critical factors in the communications process and both are substantially dependent upon the level of noise energy present in the input signal. Therefore, it is necessary to know the amplitude of noise levels under which the correlation synchronization process can function.
In accordance with the present invention there is provided an apparatus for measuring the quantity and types of errors that are generated during the synchronization process as a function of the noise level that is added to the transmission medium. The noise level can be varied to permit the generation of a quantitative functional relationship between the noise present in the signal and the errors produced by the correlator.